Powder jet dispenser for medicament inhalation therapies

ABSTRACT

A powder jet dispenser for medicament inhalation therapies, intended to be the drug pack container, incorporating a dose metering system, comprising a filling unit (27, 28, 29, 30, 31, 35) and a separation unit (25, 26) to fill a fix positioned dosage chamber (19) and to provide, after filling, air-tight separation of the filling unit from the medicament reservoir (36). The dosage chamber (19) being connected to a compression chamber (5) of a servo-assisted air compression system actuated by a manual stroke of a plunger (3) providing the compression of a spiral load spring (7). The load spring is released through a sliding control mechanism (11, 14) which is automatically actuated by the stroke of the plunger (3). The load spring (7) bears against a piston (8) which, upon release, snaps forward into said compression chamber (5) producing a jet of compressed air which reaches the dosage chamber (19), and passes the drug into the user&#39;s mouth through a nozzle (20) provided with a check valve (22) to avoid the entrance of external air.

BACKGROUND OF THE INVENTION

In the pharmaceutical field several lung diseases, like bronchialasthma, are treated with powdered drugs to be delivered, by means ofdispensing inhalation devices, in very accurate doses to be frequentlyrepeated.

A dispensing device for these drugs should guarantee an accurate andreproducible dosage, a perfect nebulization, which means the reductionof the powder to "respirable particles" having a diameter of less than 7microns, avoiding or disintegrating eventual powder lumps, and thepowderized drug isolation from the outside environment, to ensure itsstability and preservation.

These three characteristics, dosage accuracy, fineness of nebulizationand drug stability have, up to now, been obtained all together only withthe use of aerosol metered dispensers provided with a container in whichthe powderized drug is dispersed into pressurized FREON.

But the aerosol system and its relative FREON or CFC propellent shallnot be further allowed in the near future and furthermore the use ofpropeleny in general requires to add to the drug tensioactive orlubricant additives which have shown negative side effects when inhaled.

A way of administering powderizod drug able to avoid the use of CFCpropellent and additives is represented by the powder inhaler devices.

The main characteristic of these devices is that the delivery of thedrug is obtained by the air flow generated at inhalation which, passingthrough a dosage chamber containing the powderized drug, forms theparticle cloud which is then inhaled, thus avoiding the need ofpropellent.

In these systems, as the powderized drug, particles often tend to lumptogether forming too large particles to be inhaled, the user has toprovide an inhalation flow whose force is enough high to first move theparticles and then disintegrate them during their run through theinhaler conduits.

This breathing force cannot be achieved by many asthmatic patient andtherefore only very low dosage devices and drugs have demonstrated to beenough widely usable in most of the situations.

The document WO-A-9 204 068 discloses an inhalator without propellantgas comprising a triggerable pump which can be manually prechargedbefore starting inhalation and can be triggered in synchronism with therespiration. Disadvantageously, this device is very complicated and maytherefore lead to failures and problems during the operation and theassembly process. Furthermore, in operation, the dosage chamber is movedfrom the reservoir in an air channel, whereby some of the content of thedosage chamber can be lost before the air stream blows through the airchannel. The dosage accuracy is therefore not guaranteed.

To overcome this problem, some inhalers use packs capsules eachcontaining a single dose of the powderized drug, and more recentlysystems incorporating a multidose powder reservoir have been introducedon the market.

One of the most recent version of this system incorporates one or moredosage chambers, obtained as holes in a rotable element associated tothe drug reservoir, holes which are filled by dosage means containedinto the drug reservoir.

These means consist in elastic spring loaded scrapers arranged to pressagainst the perforated element surface.

These scrapers, due to their flexed position at an angle lower than 90°degrees against the perforated element and thanks to the thrust given bythe spring loading and by their resilient characteristics, do exert apressure on the micronized powder and compress it into, the dosage holeswhen they slide under them.

Nevertheless this compression of the powderized drug could create, incertain cases, some inconvenient which could compromise the doseaccuracy.

In fact the micronized powders, when compressed, tend to stick togetherand to form lumps of various and relatively large dimension, andscrapers in general, keep under compression at least the quantity ofdrug which is retained between themselves and the rigid surface againstwhich they urge.

These agglomerates are not always removed or disintegrated by thescrapers and could therefore obstacle the correct filling of the dosageholes or chambers.

Further to that this compression could create "compactings" of differentand not controllable density inside the dosage holes, thus creatingpossible variations in the delivered quantities.

The above is further particularly relevant in case of relatively largerequired doses (from 2 to 10 mg and over) as in the use of SodiumCromoglycate or of mixtures of different drugs.

In these cases, in fact, larger and mainly deeper dosage holes areneeded, which makes their filling much more difficult.

Furthermore the deeper holes reduce the effectiveness of a scraper as afilling device as, due to its shape, it cannot enter deep into the holeto be filled.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a system allowing toreplace the pressurized aerosol propellent system and its relativeadditives, with pressurized air whose pressure is generated, at themoment of the administration, by a suitable device, which is part of themedicament pack, which also incorporates a dosage system able to providedosage accuracy and reproducibility together with medicament stabilityand preservation.

A further object is to provide the possibility of a coordination betweenthe inhalation and the actuation of the device in order to allow themedicament to effectively reach the lungs of the patient.

The present invention relates to a powder jet dispenser for medicamentinhalation using environment air, compressed at the moment of thedispenser actuation, ejected, at predetermined and reproduciblequantity, pressure and speed, from a compression chamber by means of amanually spring loaded and servo-assisted piston, ejection performedthrough a passage connecting the compression chamber to the dosage onewhich is further connected to the dispenser nozzle.

Dosage chamber which is accurately and reproducibly filled by fillingmeans contained inside the powderized medicament reservoir and that,further to the chamber filling, provide for the isolation of themedicament reservoir from the outside environment, and the compressedair flow.

The above with the further advantage to allow to replace the manualcontrol of the release of the spring loaded piston and the consequent-drug delivery with a control system directly and automatically actuatedby the air flow generated at inhalation.

It is thus provided a powder jet dispenser serving as medicament packcontainer for medicament inhalation therapies comprising a dose meteringsystem having filling means and a separation unit to fill a dosagechamber arranged at the bottom of a medicament reservoir and to provide,after its filling, the air-tight separation from the medicamentreservoir, said dosage chamber being connected to a compressioncylindrical chamber formed in a tubular element which is part of an aircompression system actuated by the stroke of a plunger and accumulatingenergy by means of the compression of a spiral load spring, and thenautomatically releasing said accumulated energy of said spiral loadspring by means of a sliding control mechanism automatically actuatedeither by the continuation of the stroke of the plunger, or in amodified embodiment, by an element directly controlled by the user'sinhalation, said accumulated energy being released against a pistonwhich under the thrust of the load spring snaps forwardly into saidcompression chamber, thereby producing a jet of compressed air for themedicament delivery from the dosage chamber through a nozzle,characterized in that said filling means are rotatable and said dosagechamber is fixed, said dosage chamber being formed in the bottom of saidmedicament reservoir.

In accordance with these constructional features, it is possible torefill the dosage chamber by simply turning the filling means, which isa very simple operation for the user and provides high reliability insupplying only a limited amount of product. Furthermore, it isimpossible to lose a part of the dosage chamber content before the airstream blows through it. A high dosage accuracy and reproducibility isthereby provided. It is further provided a jet dispenser for medicareantinhalation, therapies manually actuated by means of a cylindricalplunger axially slidable inside a hollow main body, plunger whichcontains, inside its cavity, a piston subjected to the thrust of acylindrical main load spring and is slidable assembled inside a hollowcylinder forming the compression chamber for the air, and having anaxial outlet hole provided with a non return valve, said cylinder havingaxially and externally slidable mounted a control sleeve, provided witha secondary return spring, suitable to force a resilient expansibledetent ring, operating in a slotted groove formed on the hollowcylinder, to inwardly protrude and oppose the forward movement of thepiston during all the manual loading and compression of the main springby means of the pressure exerted on the plunger; plunger which at theend of its loading stroke abuts with its edge against the edge of saidcontrol sleeve and shifts it forward thus allowing the resilientexpansible detent ring to expand and therefore to release the pistonwhich, under the action of the loaded spring, moves forward with astrong snap action and produces a jet of compressed air at high speedand pressure which are predetermined by the elastic characteristics ofthe spring and by the dimensions of the compression chamber, both to bechosen in relation to the quantity and the type of drug to be delivered.

Said compressed air reaches, through a suitable passage, a dosagechamber containing the exact quantity of powderized drug to bedelivered, powder which has been previously inserted by means of thefilling and separating device contained into the drug reservoir, andgets out, in form of a mixed jet, through a nozzle provided with aseparation non return valve.

Said filling and separating device consisting in elements, connected toa turning knot, placed outside the powder dispenser, carrying two ormore brushes, or better little brooms, preferably of different lengthand softness, able to penetrate and fill the dosage chamber obtained asa hole made on the bottom of the drug reservoir, and a plug, whichseparates the dosage chamber and the compressed air flow from the drugreservoir, once the turning knob is returned to a marked position afterthe turn made to obtain the filling of the dosage chamber.

The above with the further possibility to obtain a breath control of theactuation (by inhalation) of the dispenser instead of a manual one, byassociating with the control sleeve a lever element provided with twoside arms carrying the lever rotation fulcrum consisting in two pins,passing through two diametrically opposite special slits made on thecontrol sleeve, and inserted into two blind holes made on the hollowcylinder, forming the compression chamber. Said lever element provided,associated with each of the fulcrum pins, with a cam, interacting withthe suitably shaped slit profile of the control sleeve, and having itsterminal part, opposite to said two side arms, shaped in the form of asemicylindrical vane which is inserted into a special control chamber,formed into the external body of the dispenser, provided with slits forthe air inlet which are normally closed by the same vane, and connected,by means of suitable passages, made inside the dispenser body, to thedispenser mouthpiece.

The above suitably arranged so that the vane, at the inhalation made bythe patient, and the consequent depression created into the controlchamber, moves to let the air in causing the rotation of the lever, ofwhich it is part, on its fulcrum pins.

Rotation which, thanks to the cams, provided on the side arms of thelever, acting against the profile of the slits made into the controlsleeve, causes the shift of the latter and the consequent release of theresilient expansible detent ring and of the piston which snaps forward,instantly releasing the energy accumulated while manually, loading thema-in spring and causing a compressed air jet at high and predeterminedspeed and pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings show in different scales, by way of nonlimiting examples, a basic embodiment of the article of the inventionand a simplified and modified version, incorporating the breath controlactuation.

FIG. 1.--Is an axial sectional view of the powder dispenser beingconcerned, with its internal components parts, the drug reservoir andthe nozzle, in a basic embodiment and at the rest position with theplunger ready to start the stroke to load the main spring.

FIG. 2.--Is an axial sectional view similar to FIG. 1 with the springloading stroke almost completed and immediately before the piston snapsand the consequent air compression occurs.

FIG. 3.--Is an axial sectional view similar to FIGS. 1 and 2 with thedispenser at the end of the delivery.

FIG. 4.--Is an axial sectional view of a detail of the dispenser showingthe drug reservoir, containing the filling and separation device, andthe dosage chamber.

FIG. 5.--Is a plan detail view of the filling and separation element.

FIG. 6.--Is a side detail view of one of the filling brooms.

FIG. 7.--Is an axial partly sectional view of a modified embodiment ofthe dispenser showing the application of the breath control actuation,at the rest condition similar to the one described in FIG. 1.

FIG. 8.--Is an axial partly sectional view similar to FIG. 7 but withthe dispenser during the drug delivery.

FIG. 9.--Is an axial partly sectional view of the dispenser in the samerest position of FIG. 7 but axially rotated of 90°.

FIG. 10.--Is an axial partly sectional view of the dispenser in the samedispensing position of FIG. 8 but axially rotated of 90°.

FIG. 11.--Is a perspective of the lever, complete with side arms andvane, and of the inhaled air flow conveyer element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As clearly shown in FIG. 1, the powder jet dispenser for medicament oralinhalation being concerned, which is at the same time the medicamentpack, consists in a tubular main body 1 bearing, screwed or in other wayfixed on its upper end, the cover 2, of the powderizod drug reservoir,which support the filling system and on the opposite side axiallysliding a cylindrical cup shaped actuation plunger 3 provided withshoulder 4 on its bore and bearing a cylindrical base 6, fastened to itsbottom, intended to support and guide a cylindrical load main spring 7mounted inside a partly hollow piston 8 with blind head provided with aseal lip 9 and with a circular grove 10 intended to house, during thespring 7 loading action, part of the resilient expansible detent ring11.

Said piston 8 to which is connected the screw 32 which interacts withthe cylindrical base 6 and the cylindrical actuation plunger 3 duringthe manual resetting of the system later on described.

Under the drug reservoir the tubular main body retains a separation anddistribution head provided with a protruding cup shaped neck and with aseat to fix and retain a tubular element 13, protruding towards thecylindrical plunger 3, and intended to form the air compression chamber5 inside which the piston 8 slides, and retain in a special slottedgroove the resilient expansible detent ring 11 which tends to outwardlyprotrude but is forced, in the phases shown in FIGS. 1 and 2, toprotrude inwardly of the tubular element 13 and to enter the circulargroove 10 made on the head of the pistor, 8, thus opposing the forwardmovement of the same piston 8.

This position and locking function of the elastic expansible detent ring11 is granted by the sliding control sleeve 14 pushed towards theshoulder 4 of the cylindrical plunger by the secondary return spring 15.

The control sleeve 14 is internally shaped in such a way that it can actas a cam for the resilient expansible detent ring 11 and to keep itcompressed during all the loading action of the main spring 7 obtainedby pressing the cylindrical plunger 3.

At the end of the main spring loading phase, as shown in FIG. 2, theshoulder 4 of the cylindrical plunge 3 abuts against the lower edge ofthe control sleeve 14.

The further movement of the cylindrical plunger 3 causes the controlsleeve 14 to shift and, thanks to its internal cam profile, to permitsthe resilient expansible detent ring to expand.

As result its inward protruding portion retracts from the circulargroove 10 on the head of the piston 8, and the piston, due to the actionof the loaded spring 7, moves forward with a strong snap action,reaching the position of FIG. 3, and causes the compression of the airvolume contained in the compression chamber 5 and its expulsion throughthe central passage 16, of the tubular element 13, provided at itsoutlet with a sphere check valve 17; passage 16 which is connected to achamber 18, formed inside the head 12, containing a little load springfor the check valve 17.

The chamber 18 is connected, by a lateral passage, to the dosage chamber19, containing the exact dose of powderized drug to be delivered, whichis further connected to the drug reservoir from which it is filled bythe filling device, better described later on, which, being providedwith the plug 26, also grant the closure and the separation of the samedosage chamber from the drug reservoir chamber 36. This separation avoidany compressed air dispersion or drug return into the drug reservoir,during the compressed air flow and the consequent drug delivery, thusgranting that all the drug contained into the dosage chamber 19 iseffectively delivered and exploiting all the compressed air forceavailable.

The dosage chamber 19 which is fixed with respect to the main body 1, isalso provided with an outlet passage connected to the nozzle 20 providedwith a calibrated passage 21 and containing a sphere check valve 22having the function to prevent, after the drug delivery, the entrance ofoutside air.

In order to facilitate the use of the dispenser the nozzle 20 issurrounded by a short coaxial hose or mouthpiece 23 formed in theexternal casing 24 of the main body 1 of the dispenser.

At the end of the drug delivery and in the position described in FIG. 8,after a first phase of automatic return, due to the thrust of thesecondary spring 15 against the control sleeve 14 which acts against theshoulder 4 of the plunger 3, the unit is returned to the positiondescribed in FIG. 1 by exerting a manual pull action on the cylindricalplunger 3.

This action also reset the piston 8, thanks to the head of the screw 32acting against an inner shoulder of the cylindrical base 8 fixed to thecylindrical plunger 3.

FIGS. 4, 5 and 6 show in a more detailed way the filling and separationdevice contained in the drug reservoir chamber 36 placed under the cover2.

This device consists of a turning element 25, provided with verticalface 35, perpendicular to the bottom of the drug reservoir, carrying aspring loaded plug 26 made of resilient material, like rubber, and of afurther turning element 27 provided with three arms, two of which 28,each carrying a filling brush or broom 29, and a central one, 30,carrying a preferably softer and longer broom 31 suitable to deeplyintroduce the powder inside the dosage chamber 19.

The cover 2 is axially holed and retains after assembling a seal ring33, an actuation knob 34 provided with a square section stem holding theelements 25 and 27 which can therefore be turned by the outside.

The uniform and reproducible filling of the calibrated dosage chamber19, is performed by vertically holding the dispenser with the drugreservoir on the top and by turning clock or anticlockwise for 380° theknob 34 and consequently the elements 25 and 27.

During this rotation the component elements perform the followingfunctions: the broom 31, mounted on the arm 30 of the element 27, movesthe micronized powder towards and into the dosage chamber 19 by enteringinto it and allowing the filling of its deeper portion, the brushes orbrooms 29, mounted on the arms 28 of the element 27, move the powdertowards the dosage chamber 19 and fill its upper portion, theperpendicular sides 35 of the element 25 remove the excess of powder andfinally, once the turn is completed, the plunger 26 closes, thanks tothe spring loading, the dosage chamber 19, preventing therefore the aircompressed by the device previously described or the drug contained inthe dosage chamber to enter or return into the drug reservoir chamber36.

The separation granted by the plunger 26 also ensures that thepowderized drug contained in the drug reservoir, never get in contactwith outside air, even with the one first sucked and then ejected by thecompression device.

Finally it must be noted that the small brushes or brooms are not in anyway spring loaded to press against the chamber to be filled or againstthe powderized drug and that they simply move the micronized drugtowards and into the dosage chamber, having the further task of movingand shaking the powder and to clean the edges of the dosage hole, thusremoving eventual powder agglomerates or lumps which could obstacle acorrect filling.

According to the invention the system, can be actuated by means of acontrol provided by the user's inhalation instead of by the previouslydescribed manual control obtained by continuing the actuation stroke ofthe plunger 3 after the first phase of loading the main spring 7.

Some modifications developed for this instance are shown in FIGS. 7 to11 and these modifications still based on the same operating principle,will be described here below.

FIG. 7 shows in a schematic way the inhalation actuated dispenserwherein the modified control sleeve 45, is provided with twodiametrically opposite special slots 46 which house the cams 47, formedon the side arms 48 of the lever control element 49, and allow thefulcrum pins 50, of said control lever 49, to pass through and enter theblind holes 51 made on the tubular element 44 which forms thecompression chamber 5 and retains, in a special slotted groove, the sameresilient expansible detent ring 11 of the basic embodiment.

Said control lever 49, as better described in FIG. 11 consists of thetwo side arms 48 carrying the cams 47 and the fulcrum pins 50, of acentre lever arm and of an element, which is sensible to the depressioncaused by the inhalation, formed as a semicylindrical vane 53.

The semicylindrical vane 53 is housed into an air flow conveyer element54, provided with slits 55, for the air inlet, and with a slit 56 toslidably house the centre arm of the control lever 49, and which isinserted and fixed into a side into an opening of the chamber 58 formedinto a side portion of the main body 37; the whole such arranged that,at rest condition, the air inlet slits 55 are normally closed by thesemicylindrical vane 53.

Furthermore, on respect to the basic embodiment, the control shoulder 4has been eliminated from the actuation plunger 3 as no longer necessary,because in the breath actuated version the plunger, now 38, has the onlyfunction to compress and load the main spring 41.

Finally the dispenser described it, FIGS. 7 to 10 is provided withanother secondary spring 43 which resets the plunger start position atthe end of the delivery, as described later on.

The upper portion of the dispenser, not described in details in FIGS. 7to 10, consists of the same drug reservoir, the same filling system andthe same dosage chamber, which is placed in a passage between the aircompression chamber 5 and the nozzle 59, of the basic embodiment.

After the dosage chamber filling, performed as previously described, thepatient takes the mouthpiece 57 at his mouth and, while holding thedispenser, presses the cylindrical plunger 36 until it stops.

This action exerted on the plunger 36 causes the loading of the mainspring 41, with the consequent energy accumulation within the same, asthe piston 42 cannot move forward, as retained by the resilientexpansible detent ring 11 which is partially inserted into the circulargroove 10 of the piston 42 and the expansion the same detent ring 11 isprevented by the control sleeve 45.

At this point and while keeping pressed the cylindrical plunger 38, thepatient makes an inhalation act which causes, through the mouthpiece 87and the special passages made in the main body 37, a depression in thecontrol chamber 58.

This depression causes the movement of the semicylindrical vane 53, andof the lever 49, which is necessary to let the air in through the slits55 made on the air flow conveyer 54.

The result is 8 rotation of the lever 49, on its fulcrum pins 50, and ofthe corresponding cams 47 which, acting against the face 52 of the slots46 made on the control sleeve 45, cause the upward movement of thelatter as shown in FIGS. 2 and 4.

This upward movement of the control sleeve 45 releases the resilientexpansible detent ring 11, which expands, then stopping its detentaction on the piston 42 which snaps forward, instantly releasing all theenergy previously accumulated by loading the main spring 41 and causinga jet of compressed air at predetermined and reproducible speed andpressure which carries, as described for the basic embodiment, thepowder contained in the dosage chamber, through the nozzle, to the mouthand the lungs of the patient.

The perfect synchronization between the drug delivery and the user'sinhalation, is granted, further than by the instantaneous action of thedispenser and by the fact that anybody, once started an inhalation act,tends to fully complete it, by the fact that the depth and the shape ofthe air flow conveyer 54 are such to allow an effective air passage,between it and the semicylindrical vane 53 edges, only when the controldevice has been actuated and the drug delivery occurred.

Once the delivery has been performed and the cylindrical plunger 38released, the return secondary spring 43 returns the unit cylindricalplunger 38/piston 42 to the rest or start position while the returnsecondary spring 15 provides for the return to the rest or startposition of the control sleeve 45 and of the lever 49, and therefore ofthe resilient expansible detent ring 11, as shown in FIG. 7 and FIG. 9.

As to the remainder, all as described and shown, made of any suitablematerial, liable to modifications and improvements, still within thebasic principle of the invention.

What is claimed is:
 1. A powder jet dispenser serving as a medicamentpack container for medicament inhalation therapies, comprising:a mainbody portion(1); a nozzle (20); a drug reservoir (36) having a bottomside; a dosage chamber (19) arranged at the bottom side of said drugreservoir (36); and a dose metering system, comprising:filling means forfilling said dosage chamber (19), said filling means comprising:aseparation unit (25, 26) for providing, after the filling of said dosagechamber, an air-tight separation of said filling means from said drugreservoir (36); an air compression system comprising:a cylindricalcompression chamber (5) formed in a tubular element (13); a plunger (3),the stroke of said plunger being adapted to actuate said air compressionsystem; a spiral load spring (7) adapted to accumulate energy by meansof its compression; a sliding control mechanism (11, 14) adapted toautomatically release the accumulated energy of said spiral load spring(7) automatically actuated by the stroke of the plunger (3), whereinsaid dosage chamber (19) is connected to said compression chamber (5);and a piston (8), wherein said accumulated energy is released againstsaid piston (8) which is adapted, under the thrust of said load spring(7), to snap forwardly into said compression chamber (5) therebyproducing a jet of compressed air delivering the drug from the dosagechamber (19) through said nozzle (20), wherein said filling means isrotatable and said dosage chamber (19) is fixed with respect to saidmain body portion (1).
 2. The powder jet dispenser according to claim 1,wherein said main body portion (1) has upper and lower ends, bearing onits upper end a fixed, screwed cover (2) which closes said drugreservoir (36) and disposed at the lower end said plunger (3) which isaxially slidable, hollow, cylindrical and manually actuatable and whichis provided with two bores forming a shoulder (4) and a plane bottombearing a cylindrical base (6) having a seat for supporting andarresting a spiral load main spring (7) assembled in a special blindbore in the piston (8) which is axially slidable in the tubular element(13) forming said cylindrical compression chamber (5) fixed and retainedby a distribution and separation head (12), said distribution andseparation head (12) being provided with a downwardly protruding neckbearing a secondary return spring (15) resting against a seat formed ina control sleeve (14) which is axially slidable over the tubular element(13), said distribution and separation head (12) being fixed to theupper end of the main tubular body (1) under the drug reservoir chamber(36) which is provided with an air passage chamber (18) containing asphere check valve (17) in correspondence with a center outlet hole (16)provided at an end of the tubular element (13) in which the piston (8)slides, said air passage chamber (18) being connected by a passage tothe stationary dosage chamber (19) having an upper opening connected tothe drug reservoir chamber (36) through which it can be filled, and anoutlet passage connected to the nozzle (20).
 3. A powder jet dispenseraccording to claim 1, wherein the nozzle (20) is provided with anon-return sphere check valve (22) for forming an air-tight seal.
 4. Apowder jet dispenser according to claim 1, wherein a head of the piston(8) is provided with a circular seal lip (9).
 5. The powder jetdispenser according to claim 1, wherein said tubular element (13) has aslotted groove formed therein, said sliding control mechanismcomprises:a resilient expansible detent ring (11) which is retained inthe slotted groove of the tubular element (13); a circular groove (10)formed on the head of the piston (8); and a control sleeve (14) having abore which comprises a cam profile adapted to force said resilientexpansible detent ring to protrude inwardly towards the head of thepiston (8) and to enter said circular groove (10), said control sleevebeing axially slidable over the tubular element (13) to prevent aforward movement of the piston (8) during a loading stroke of the loadspring (7) until the control sleeve (14) shifts upwardly releasing theresilient expansible detent ring (11) and allowing the piston (8) tosnap forwardly under the thrust of the load spring (7).
 6. The powderjet dispenser according to claim 5, wherein said main body portion (1)has upper and lower ends, bearing on its upper end a fixed, screwedcover (2) which closes said drug reservoir (36) and disposed at thelower end said plunger (3) which is axially slidable, hollow,cylindrical and manually actualable and which is provided with two boresforming a shoulder (4) and a plane bottom bearing a cylindrical base (6)having a seat for supporting and arresting a spiral load main spring (7)assembled in a special blind bore in the piston (8) which is axiallyslidable in the tubular element (13) forming said cylindricalcompression chamber (5) fixed and retained by a distribution andseparation head (12), said distribution and separation head (12) beingprovided with a downwardly protruding neck bearing a secondary returnspring (15) resting against a seat formed in the control sleeve (14)which is axially slidable over the tubular element (13), saiddistribution and separation head (12) being fixed to the upper end ofthe main body portion (1) under the drug reservoir chamber (36) which isprovided with an air passage chamber (18) containing a sphere checkvalve (17) in correspondence with a center outlet hole (16) provided atan end of the tubular element (13) in which the piston (8) slides, saidair passage chamber (18) being connected by a passage to the stationarydosage chamber (19) having an upper opening connected to the drugreservoir chamber (36) through which it can be filled, and an outletpassage connected to the nozzle (20).
 7. A powder jet dispenseraccording to claim 1, wherein the dose metering system furthercomprises:a turning knob (34) provided with a stem disposed in the drugreservoir, the stem having a square-shaped end; a cover (2) having ahole and bearing, the turning knob positioned in a sealed manner througha hole; and a second turning element (27) provided with three arms,wherein two (28) of said three arms each carry a filling brush or broom(29), and the third (30) remaining arm located centrally between saidtwo filling brush or broom carrying arms, carries a softer and longerbroom (31), suitable to deeply introduce the powder deeply into thedosage chamber (19) which is formed as a hole in the bottom of the drugreservoir chamber (36) and wherein said separation unit comprises: anelement (25) disposed on the square-shaped end of said turning knob(34), said element (25) provided with vertical faces (35) perpendicularto the bottom side of the drug reservoir; separation means carried bysaid element (25) for separating in a sealed manner said dosage chamber(19) from said drug reservoir (36).
 8. A powder jet dispenser accordingto claim 7, wherein the turning knob (34) rotates over a range of 360°.9. A powder jet dispenser according to claim 7, wherein said means forseparating, upon rotating said turning knob (34) to fill said dosagechamber (19), separates in a sealed manner said dosage chamber (19) fromsaid drug reservoir (36) upon completion of the filling rotation,thereby preventing any compressed air dispersion or drug to return intothe drug reservoir (36) during delivery of the drug.
 10. A powder jetdispenser serving as medicament pack container for medicament inhalationtherapies comprising:a main body portion (37); a nozzle (59); a drugreservoir (36); a dosage chamber (19) arranged at the bottom of saiddrug reservoir (36); and a dose metering system comprising:filling meansadapted to fill said dosage chamber (19), said filling meanscomprising:a separation unit (25, 26) adapted to provide, after thefilling of said dosage chamber, an air-tight separation from the drugreservoir (36), said dispenser further comprising: an air compressionsystem comprising:a compression cylindrical chamber (5) formed in atubular element (44); a plunger (38), the stroke of said plunger beingadapted to actuate said air compression system; a spiral load spring(41) adapted to accumulate energy by means of its compression; a levercontrol element (49); a sliding control mechanism (11, 45) adapted toautomatically release said accumulated energy of said spiral load spring(41), said sliding control mechanism (11, 45) being automaticallyactuated by said lever control element (49) directly controlled by auser's inhalation, said dosage chamber (19) being connected to saidcompression chamber (5); and a piston (42), said accumulated energybeing released against said piston (42) which is adapted, under thethrust of said load spring (41), to snap forwardly into said compressionchamber (5), thereby producing a jet of compressed air for delivering adrug from the dosage chamber (19) through said nozzle (20, 59), whereinsaid filling means is rotatable and said dosage chamber (19) is fixedwith respect to said main body portion (37).
 11. A powder jet dispenseraccording to claim 10, wherein the head of the piston (42) is providedwith a circular seal lip (9).
 12. A powder jet dispenser according toclaim 10, wherein said sliding control mechanism comprises:a resilientexpansible detent ring (11) retained in a slotted groove of the tubularelement (44); a groove (10) formed on a head of the piston (42); and acontrol sleeve (45) having a bore which comprises a cam profile, saidcam profile being adapted to force said resilient expansible detent ringto protrude inwardly towards the head of the piston (42) and to entersaid groove (10), said control sleeve being axially slidable over thetubular element (44), thus preventing a forward movement of the piston(42) during the loading stroke of the load spring (41) of the plunger(38) until the control sleeve (45) shifts upwardly releasing theresilient expansible detent ring (11) and allowing the piston (42) tosnap forwardly under the thrust of the load spring (41).
 13. A powderjet dispenser according to claim 12, wherein one end of the levercontrol element (49) is associated with a control sleeve (45) throughtwo arms (48), wherein the two arms (48) carry two fulcrum pins (50)which pass through two diametrically opposite slots (46) formed in thecontrol sleeve (45) and enter two blind holes (51) formed in a modifiedtubular element (44); each of the fulcrum pins (50) is connected to acam (47) housed in the slots (46) of the control sleeve (45) andinteracts with upper faces (52) of the slots (46); and another end ofthe lever control element (49) is formed opposite to the two arms (48)as a semicylindrical vane (53) and placed in a special control chamber(58) formed in said main body portion (37) and is connected by means ofsuitable passages with a mouthpiece (57) of the dispenser.
 14. A powderjet dispenser according to claim 13, wherein the special control chamber(58) which contains the semicylindrical vane (53) of the lever controlelement (49), is provided with an opening into which is inserted andfixed an air flow conveyer (54) provided with slits (55) for allowingair to enter and with a slit (56) to slidably receive the level controlelement (49) housing the semicylindrical vane (53); wherein inhalationby a user creates through the mouthpiece (57) and the special passagesin the main body (37) a subatmospheric pressure in the control chamber(58) which causes movement of the semicylindrical vane (53) from itsrest position in which it normally closes the slits (55), to a positionin which said air can enter, and causing the lever control element (49)to rotate on the fulcrum pins (50) and the associated cams (47), whichby interacting with the upper faces (52) of the slots (46) formed on thecontrol sleeve (45) forces the control sleeve (45) to shift allowing theresilient expansible detent ring (11) to expand, thus releasing thepiston (42) which snap forwardly, under thrust of the load spring (41)previously loaded by a compression stroke of the plunger (38), producinga jet of compressed air at a predetermined pressure and speed.
 15. Apowder jet dispenser according to claim 14, wherein the inner surface ofthe air flow conveyer (54) matches the outer surface of thesemicylindrical vane (53) and said conveyer (54) has a depth which ishigher than the depth of said vane (53) at such an extent to force thecontrol lever (49) to rotate long enough for delivery of the drug tooccur, before air is allowed to enter the control chamber (58).
 16. Apowder jet dispenser according to claim 10, wherein one end of the levercontrol element (49) is associated with a control sleeve (45) throughtwo arms (48), wherein the two arms (48) carry two fulcrum pins (50)which pass through two diametrically opposite slots (46) formed in thecontrol sleeve (45) and enter two blind holes (51) formed in a modifiedtubular element (44); each of the fulcrum pins (50) is connected to acam (47) housed in the slots (46) of the control sleeve (45) andinteracts with upper faces (52) of the slots (46); and another end ofthe lever control element (49) is formed opposite to the two arms (48)as a semicylindrical vane (53) and placed in a special control chamber(58) formed in said main body portion (37) and is connected by means ofsuitable passages with a mouthpiece (57) of the dispenser.
 17. A powderjet dispenser according to claim 16, wherein the special control chamber(58) which contains the semicylindrical vane (53) of the control lever(49), is provided with an opening into which is inserted and fixed anair flow conveyer (54) provided with slits (55) for allowing air toenter and with a slit (56) to slidably receive the control lever (49)housing the semicylindrical vane (53); wherein inhalation by a usercreates through the mouthpiece (57) and the special passages in the mainbody portion (37) a subatmospheric pressure in the control chamber (58)which causes movement of the semicylindrical vane (53) from its restposition in which it normally closes the slits (55), to a position inwhich said air can enter, and causing the control lever (49) to rotateon the fulcrum pins (50) and the associated cams (47), which byinteracting with the upper faces (52) of the slots (46) formed on thecontrol sleeve (45) forces the control sleeve (45) to shift allowing theresilient expansible detent ring (11) to expand, thus releasing thepiston (42) which snap forwardly, under thrust of the load spring (41)previously loaded by a compression stroke of the plunger (38), producinga jet of compressed air at a predetermined pressure and speed.
 18. Apowder jet dispenser according to claim 17, wherein the inner surface ofthe air flow conveyer element (54) matches the outer surface of thesemicylindrical vane (53) and said conveyer (54) has a depth which ishigher than the depth of said vane (53) at such an extent to force thecontrol lever (49) to rotate long enough for delivery of the drug tooccur, before air is allowed to enter the control chamber (58).
 19. Apowder jet dispenser according to claim 10, wherein the dose meteringsystem further comprises:a turning knob (34) provided with a stemdisposed in the drug reservoir, the stem having a square-shaped end; acover (2) having a hole and bearing the turning knob positioned in asealed manner through a hole; and a second turning element (27) providedwith three arms, wherein two (28) of said three arms each carry afilling brush or broom (29), and the third (30) remaining arm locatedcentrally between said two filling brush or broom carrying arms, carriesa preferably softer and longer broom (31), suitable to introduce thepowder deeply into the dosage chamber (19) which is formed as a hole inthe bottom of the drug reservoir chamber (36), and wherein saidseparation unit comprises: an element (25) disposed on the square-shapedend of said turning knob (34), said element (25) provided with verticalfaces (35) perpendicular to the bottom side of the drug reservoir (36);separation means carried by said element (25) for separating in a sealedmanner said dosage chamber (19) from said drug reservoir (36).
 20. Apowder jet dispenser according to claim 19, wherein the turning knob(34) rotates over a range of 360°.
 21. A powder jet dispenser accordingto claim 19, wherein said means for separating, upon rotating saidturning knob (34) to fill said dosage chamber (19), separates in asealed manner said dosage chamber (19) from said drug reservoir (36),upon completion of the filling rotation, preventing any compressed airdispersion or drug to return into the drug reservoir (36) duringdelivery of the drug.